Less Difference between Office and Ambulatory Blood Pressure in Women than in Men Both Before and During Antihypertensive Treatment

In 199 subjects (56% women) with a diastolic blood pressure (BP) of 95-115 mmHg, 5 mg of either amlodipine or felodipine extended release (ER) was given for 4 weeks following 4 weeks of placebo-treatment. BP was measured by conventional clinic BP technique and by 24-h ambulatory BP monitoring (Spacelab 90202/90207). Men and women had identical clinic BP at baseline and it was lowered equally much by 4 weeks of treatment (men: 158/101 and 147/93, women: 159/102 and 149/93 mmHg, respectively). However, ambulatory BP was higher in women than in men both before and after treatment (men: 145/91 and 134/85, women: 149/95 and 140/89 mmHg, respectively, p < 0.05 for both comparisons). The difference between clinic BP and daytime ambulatory BP was higher in men than in women (systolic men: 8.1 +/- 14, women: 3.7 +/- 15 mmHg, respectively, p = 0.04; diastolic men: 5.5 +/- 8.0, women: 2.1 +/- 8.3 mmHg, p = 0.004). The correlation between the treatment effect measured by ambulatory and clinic BP was poor (systolic r = 0.26, p < 0.0001; diastolic r = 0.17, p = 0.03) and was unaffected by exclusion of subjects with normal ambulatory BP. The poor correlation between treatment effects measured as clinic and ambulatory BP is intriguing, and suggests that using ambulatory BP instead of clinic BP for monitoring the treatment of hypertension could affect the clinical outcome.